The Astronomy Tower is the tallest tower at Hogwarts Castle. It is where students study the stars and planets through their telescopes in Astronomy lessons with ProfessorAurora Sinistra. This is usually done at midnight, when the stars are best seen.[1] The tower is generally out-of-bounds except for classes.[1]

Structure

The Tower from behind

The tower is the tallest in Hogwarts, it lies almost directly above the front doors of the castle. The tower is also surrounded by a parapet and is tall enough to have a perfect view of the starry sky.

In the film adaptation of Harry Potter and the Half-Blood Prince the tower is directly over the Transfiguration Courtyard. This is the reason for the courtyard to have changed shape in both the film and the video game. Unlike the book, the tower isn't the tallest tower at Hogwarts and doesn't have a complete view of the night sky. Also, its location makes witnessing Hagrid being attacked by Ministry officials by the Fifth years taking the Astronomy O.W.L.s in Order of the Phoenix impossible, as the Astronomy Tower is located far east of the castle and would not have clear view of Hagrid's Hut (this event was not featured in the films).

In Harry Potter and the Philosopher's Stone, it is stated that students are only allowed to enter the tower during Astronomy lessons. However, in the video game adaptation of Half-Blood Prince, Harry can freely enter it. It is possible that the rule applies to first years but not to sixth years.